The all-female free divers of Jeju island have a ‘superpower’ of their genes

A pair years in the past, Melissa Ilardo discovered herself aboard a motorboat traversing the ocean round Jeju Island, which sits some 50 or 60 miles off the coast of South Korea. Earlier than the vessel had even come to a cease, an older girl in a wetsuit, fins and a masks stepped into the water. Two others adopted her.

These ladies, whose plunge Ilardo captured on video, belong to a protracted line of feminine freedivers on Jeju Island referred to as the Haenyeo.

They swam off, every with a web bag in tow to gather seafood to eat and promote. “Things like abalone, sea urchins … seaweeds sometimes,” says Ilardo, an evolutionary geneticist on the College of Utah. The Haenyeo routinely dive in waters that she says are 50° Fahrenheit on the floor at finest.

“One of the first times I was there,” Ilardo remembers, “it was snowing. They said as long as there’s not a risk that they’re going to be blown away to sea, then they still go out in the water, no matter how cold it is.”

The ladies begin diving as ladies and proceed nicely into outdated age, throughout all of life’s milestones. “They dive throughout their whole pregnancy,” says Diana Aguilar-Gómez, a inhabitants geneticist at UCLA. “They say they just dive until basically before they give birth,” and are again within the water a couple of days later.

Ilardo wished to know the way the Haenyeo are able to enduring such an excessive life-style, she says: “How evolution might have shaped the Haenyeo to be better divers, to dive more safely, to dive for longer.”

In a examine revealed in Cell Stories, Ilardo, Aguilar-Gómez, and their colleagues reveal the diversifications that make the Haenyeo’s superpower potential. It is a mixture of physiological and genetic modifications, a few of which seem to have had an influence on all the inhabitants of Jeju Island.

A ‘foolish’ experiment with clear outcomes

Ilardo determined to check the Haenyeo to different aged ladies on Jeju Island who aren’t divers however have an analogous genetic background, and to nonetheless others off island who aren’t associated. There have been about 30 in every group.

A Haenyeo diver swims to catch turban shells and abalones on Nov. 6, 2015.

Chung Sung-Jun/Getty Photos

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Chung Sung-Jun/Getty Photos

There was one downside: “You can’t take 70-year-old women who have never been diving and throw them in the open ocean,” says Ilardo.

Thankfully, there is a workaround. It is referred to as a simulated dive. “You hold your breath and put your face in a bowl full of cold water,” says Ilardo, “and your body responds as if you’re diving. Your heart rate will drop measurably.”

The Haenyeo discovered the experiment just a little foolish. “They said getting in the ocean, being underwater, that’s diving. Whatever this is, this isn’t diving,” remembers Ilardo. “But they still held their breath long enough that we were able to elicit a response.”

That response was important: The Haenyeo coronary heart price fell by about 50% greater than their non-diving friends. “We had one diver whose heart rate dropped over 40 beats per minute in 15 seconds,” says Ilardo.

She concludes that that is basic physiological adaptation. That is as a result of the cohort of different ladies from Jeju — the non-divers with comparable genetic make-up — did not expertise the identical drop in coronary heart price. The distinction between the 2 teams is because of a lifetime of diving expertise.

Pushing the physique to its limits

Subsequent, the researchers took saliva samples to search for genetic variations between the completely different teams. Everybody from Jeju — each the Haenyeo and the non-divers — had mainly the identical genes, which means that the individuals of this island seem to have been genetically sculpted by generations of divers.

“What this suggests is that everybody in Jeju has an equally likely chance of being a descendant of a diver,” says Ilardo.

Two genes stood out within the evaluation. The primary one appears to be associated to chilly tolerance. “Maybe that protects them from hypothermia in ways that we don’t fully understand yet,” she suggests.

The second gene was related to blood stress, seemingly related to blood vessel construction and performance.

“Diving increases your blood pressure,” says Aguilar-Gómez, who did this work as a PhD pupil at UC Berkeley, “and particularly through pregnancy that can be very dangerous. It can increase your risk for preeclampsia,” and different doubtlessly life-threatening problems.

“Even if you didn’t die, probably women that were protected against this would be more likely to have more children,” she says, and extra prone to cross their protecting genes alongside.

As well as, Jeju Island has one of many lowest charges of stroke mortality in all of South Korea. And since stroke may result from hypertension, Ilardo thinks the low mortality may very well be associated to this second protecting gene.

“Wouldn’t it be amazing if by studying divers in Korea, we can translate these findings to develop a therapeutic that protects people from stroke around the world?” says Ilardo. “By studying these populations, it can lead to discoveries that could have really Important implications for people everywhere.”

Stephen Cheung research excessive physiology at Brock College in Canada and wasn’t concerned within the analysis. He says he finds the work fascinating. “By pushing the body to its limits,” he says, “we get a better sense of where those limits are, but also just what the human body is capable of.”

Ilardo says she and her staff returned to Jeju to share the outcomes with the Haenyeo — whose lifestyle is dwindling — and ensure they knew the top-line conclusion.

“These women are extraordinary,” she says. “Their biology is amazing and what they do is amazing. And so I think it’s really important to celebrate just how unique and special these women are — and how it’s changed their bodies and the bodies of other people on this island.”